Ignition device for arc lamps



Ap 1952 P. E. c. NUQUET IGNITION DEVICE FOR ARC LAMPS Filed July 16, 1951 Patented Apr. 1, 1952 IGNITION DEVICE FOR ARC LAMPS Pierre E. C.

Nuquet,

Boulogne-Billaneourt,

France, assignor to Maison Breguet (S-ociete Anonyme), Paris, France,a company of France Application July 16, 1951, Serial No. 236,950 In France July 21, 1950 4 Claims. (Cl. 314-46) It is well known that arc-lamps are usually provided with a motor for promoting forward motion of the carbon electrodes as they are consumed.

The present invention has for its object an ignition device for arc-lamps according to which said motor is used for promoting automatic ignition of the lamp.

For obtaining a slow and regular forward motion of the carbon electrodes by means of an electric motor rotating at a certain speed, this motor is usually coupled with a reduction gear, at least one stage of which is essentially constituted by a worm shaft meshing with a worm wheel.

According to the invention, the Worm is slidably mounted on the shaft supporting it, whereas the worm wheel can be locked by an electromagnetically operated pawl the feeder circuit of which depends on the current of the arc, the

worm being able, during its translatory movement, when the wheel is locked, to shift at least one of the carbon electrodes towards the other one against a return spring.

Thus, when the arc is not ignited, the worm Wheel is at rest. When the carbon electrodes of the are are charged at the same time as the motor is started up, the worm wheel being locked through the electromagnetic pawl, this wheel acts like a nut along which the worm can move forward. During this motion, this worm shifts one of the carbon electrodes so far as to bring it into contact with the other electrode, so that the circuit of the arc is closed and the electromagnetic pawl being excited is released. The worm wheel is thus able to rotate and the carbon electrodes are separated through the return spring, whereby ignition of the arc is promoted while the pawl keeps being excited. Therefore, the worm is returned to its original position while the motor is still in rotation and is able to promote the forward motion of the carbon electrodes for taking up the wear of same.

According to an advantageous embodiment of the invention, the electromagnet of the pawl, when in excited position, locks the movable part which can be shifted by the worm, so that any bringing together of the carbon electrodes of the arm is prevented during operation of same.

It may be noticed that this device does not disturb the forward motion of the carbon electrodes as this motion is automatically stopped by the electromagnetic pawl when the are is switched off and so long as the operation of ignition has not been effected.

The device according to the invention has the advantage that the full power of the motor is successively used for igniting the lamp and for 2 shifting the carbon electrodes, so that it is not necessary to increase the power of this motor for enabling it to assume its complementary function.

In the following detailed description of the invention, reference is had to the accompanying drawing-which forms part hereof.

In the drawing the single figure shows diagrammatically an arc-lamp provided with an ignition device according to the invention.

The arc-lamp shown on this figure is fed through the positive terminal I and through the negative terminal 2 of a source of direct current. The terminal I is connected through a conductor 3 to the positive carbon electrode 4, through a sliding contact 5 provided with cooling-flanges. The terminal 2 feeds the negative carbon electrode 6 through a conductor I passing through the electromagnet 8 which is to be described later. Across the terminals l and 2, is mounted a motor 9 the outgoing shaft I of which can be grooved, for example, and supports the worm I l which extends into a pusher I2.

The worm meshes with a worm wheel I3 which is provided on one of its faces with lugs I4 regularly arranged at its periphery. The Wheel I3 is integral with a shaft I which drives, through a bevel gear It, a pinion I'I meshing with a rack promoting the forward motion of the electrode 4.

The shaft I5 supports moreover a worm I8 meshing with a worm wheel I9 supported by a shaft which is connected, for example through a Cardan joint 2|, to a shaft 22 which promotes the forward motion of the negative electrode 6 through the bevel gear 23. Besides, the shafting including the shafts 20 and 22 and the Cardan joint -2I can be wholly or partly substituted by a flexible shaft. The lugs l4 cooperate with a pawl 24 urged by a return spring 25 for locking the worm wheel I3. The pawl 24 can be actuated by one of the branches of a bent lever 26 pivoted around the axle 21, the other branch of the bent lever being connected to the rod 28 of the plunger of the electromagnet 8. This rod 28 is urged by a return spring 29.

The frame 30 supporting the electrode 6 is movable around the axle 3| Which is perpendicular to the plane of the figure and which has an extension passing across the centre of the Cardan joint 2I. The frame supports two arms 30:; and 30b, the first of which cooperates with the extension I2 of the worm I I whereas the second of them cooperates with the extension 28a of the rod 28 of the plunger of the electromagnet. This frame 30 is urged by a return spring 32 which tends to shift it back into the position shown on the figure.

When the break switch 33, which controls the feed of the are together with the feed of the motor 9, is open, the electromagnet 8 is not excited. Therefore, the device isin the position shown on the figure, i. e. the pawl 24 is'incontact with one of the lugs 14 and locks the worm wheel [3.

When the break switch 33 is closed, the motor 9 starts rotating and the worm wheel being locked the worm ll moves forward along this wheel in screwing itself in the teeth of said wheel. It

is therefore shifted through a helicoidal motion,

towards the left part of the figure. Through this motion, the worm i I rotates the frame 30 around the axle 3| by means of the pusher (2', so that the carbon electrode 6 comes into contact with worm slidably mounted on said support shaft; a

worm wheel adapted to mesh with said worm;

- gearing means connected to said worm wheel and adapted to promote said forward motion of the electrodes; an electromagnet fed in series with said. electrodes; locking means for controlling said worm wheel; means for controlling said lockthe electrode 4 and takes the position 6a shown in dot and dash line.

The circuit of the electromagnet 8 is then closed, the plunger of this magnet is attracted towards the left and through this motion it draws in the direction of the arrow the bent lever 26 against the springs and 29, so that the pawl 24 is released from the lug M. The worm wheel [3 is then able to rotate. It is then moved on the direction opposite to its normal direction of rotation, being urged by the spring 32 which shifts the frame back to itsoriginal provision; for the worm II is pushed back towards the motor and through this motion it drives the wheel Hi. The arc is then ignited and the motor keeps rotating for taking up the wear of the carbon electrodes.

The electromagnet being further excited by the current passing through the arc, the extension 28a comes into contact with the arm 3flb-so that any pivoting motion of the frame 30 is prevented and the lamp operates normally until it is switched off through opening of the break switch 33. The carbon electrodes are then stopped in the position in which they were, and a new ignition can be automatically obtained by closing the break switch 33.

As the device according to the invention promotes automatically the ignition of the arc.- lamps, it has the great advantage of enabling mg means through said electromagnet; a pivotally linked frame for supporting one of said electrodes and for promoting shifting of said last mentioned electrode towards the other one; an extension fast with said worm and adapted to control said pivoting frame; and return spring means for urging said frame towards said extension.

3. An arc-lamp having an ignition device and a device for promoting forward motion of the electrodes for taking up the wear of same, said electrodes being fed by a source of direct current, comprising in combination an 3 electric motor; a support shaft associated with said motor; a, worm slidably mounted on said support shaft; a worm wheel adapted to mesh with said worm; gearing means connected to said worm wheel and adapted to promote said forward motion of the electrodes; an electromagnet fed in series with said electrodes; locking means for controlling said worm wheel; means for controlling said locking means through said electromagnet; a pivotally linked frame for supporting one of said electrodes and for promoting shifting of the remote control and the coupling in series of a device for promoting forward motion of the electrodes for taking up the wear of same, said electrodes being fed by a source of direct current, comprising in combination an electric motor; a support shaft associated with said motor; a worm slidably mounted on said support shaft; a worm wheel adapted to mesh with said worm; gearing means connected to said worm wheel and adapted to promote said forward motion of the electrodes; an electromagnet fed by an, electric current adapted to depend on the current passing through said electrodes; locking means for controlling said worm wheel; means for controlling said locking means through said electromagnet; means for pivotally supporting one of said electrodes and for promoting shifting of said last mentionedelectrode towards the other one; and means for controlling said supporting means through said worm.

said last mentioned electrode towards the other one; an extension fast with said worm and adapted to control said pivoting frame; return spring means for urging said frame towards said extension; means for locking said pivoting frame in returned position; and means for controlling said last mentioned locking means through said electromagnet.

4. An arc-lamp having an i nition device and a device for promoting forward motion of the electrodes for taking up the wear of same, said electrodes being fed by a source of direct current, comprising in combination an electric motor; a support shaft associated with said motor; a worm slidably mounted on said support shaft; a worm wheel adapted to mesh with said worm; gearing means connected to said worm wheel and adapted to promote said forward motion of the electrodes; an electromagnet fed in series with said electrodes; locking means for controlling said. worm wheel; means for controlling said locking means through said electromagnet; a pivotally linked frame for supporting one of said electrodes and for promoting shifting of said last mentioned electrode towards the other one; an extension fast with said worm and adapted to control'said pivoting frame; return spring means for urging said frame towards said extension; means for locking said pivoting frame in returned position; means for controlling said last mentioned locking means through said electromagnet; and a flexible shaft connected to said gearing means and adapted to transmit said for ward motion to said electrode supported by said pivoting frame.

PIERRE E. C. NUQUE'I.

No references cited. 

